1. Field of the Invention
The present invention relates to a multiple image forming system for synthesizing and forming a plurality of images having different characteristics.
2. Related Background Art
Hitherto, in the case where the portions having different gradations, for example, the character portion and the photograph portion or low contrast portion mixedly exist on the same original, a density reducing dial or photograph mode selection key or the like is operated in accordance with the portion whose occupying rate is larger or with the portion to be emphasized and the images are then copied. However, according to such a method, the image in the other portion is frequently certainly sacrificed. For example, when the images were copied in accordance with the character portion, the gradations in the photograph portion become poor, so that the images in the photograph portion become hard. On the contrary, when the images were copied in accordance with the photograph portion, the density of the images in the character portion is reduced or the images in the character portion easily become fogging.
For example, when copying an original in which cut-out photograph originals and newspaper originals mixedly exist in one original proper image forming means does not exist for all of the originals such as photograph original which needs gradations and newspaper original which requires that the fogging does not occur. Therefore, in most cases, the user usually selects image forming means such that a reference original can be properly copied. Thus, even if a proper image was derived for a reference original as a base, the image of a cut-out photograph original has the poor gradations. On the other hand, in the case of a newspaper original, an image such that the background portion is fogging is obtained. It is difficult to obtain an image suitable for all of the mixed originals.
The applicant of this invention has proposed a multiple copying system in which areas of an original are designated and each area is reproduced in different color in U.S. patent application Ser. No. 830,745 (Feb. 19, 1986).
The applicant of this invention has also proposed various kinds of systems in which an image of an original is read as a form of an electric signal and a different process is performed every area having different gradation characteristic in U.S. Pat. No. 4,414,581, U.S. patent applications Ser. No. 640,539 (Aug. 14, 1984), Ser. No. 580,821 (Feb. 16, 1984), Ser. No. 022,513 (Mar. 9, 1987), Ser. No. 058,625 (Jun. 4, 1987), Ser. No. 644,558 (Aug. 27, 1984), Ser. No. 650,267 (Sep. 13, 1984), Ser. No. 022,606 (Mar. 5, 1987), etc.
However, in a copying apparatus of the type in which the light of an image is directly irradiated onto a photo sensitive material, a system for executing the process every area having a different gradation characteristic does not exist yet.